1. Field of the Invention
This invention is an improvement to my now issued U.S. Pat. No. 4,987,408. The invention relates to the detection of leakage water around household appliances. More specifically, it relates to the detection of leakage water around appliances such as air conditioning units, a hot water heater, or a clothes washing machine, and the subsequent shutting off of power and water to the appliances in response thereto.
2. Description of the Prior Art
Due to the absence of homeowners for a considerable amount of time each day, and also the fact that most multi-storied apartment buildings have many household units with each unit usually having at least three appliances which use or generate water and are subject to leakage and/or internal electrical short circuits for any one of a variety of reasons, there is a great need for water sensor systems which will monitor these various water-related appliances and respond to protect the appliance, the property, and any person that may come in contact with the appliance.
There are known systems which utilize a water collecting tray under a water appliance, such as a washing machine. An example of such a prior art device is disclosed in Thomas W. Collins' U.S. Pat. No. 3,473,553, issued on Oct. 21, 1969. In the Collins patent, a float-actuated electrical switch closes an electrical circuit when sufficient water collects in a tray. A plunger is depressed to open a normally closed valve, and a latch pin is used to hold the valve in the open position. The pin is retracted by means of a solenoid, thus permitting the valve to be closed by a spring.
Devices such as the above-described apparatus have not met with wide consumer acceptance. The main reason being due to the fact that there has to be a considerable amount of water leakage before the float will activate the switch. In some instances, the float has become inoperative due to the various deposits in the water, which cause sticking of the linkage, therefore resulting in flooding of the apartment, home or laundry room during the absence of the household occupants.
In my now issued U.S. Pat. No. 4,987,408, when water is sensed, the normally closed circuit opens, allowing storage capacitors to discharge and disable the respective operation associated with the leak. Once shut off, the controlled device cannot be turned on until the control circuit is manually reset. The storage capacitors will "remember" a fault even during a power failure. However, the problem with the capacitors is that they are only good for remembering a fault for approximately 500 hours of down time.